Bug#791676: libmpich-dev: mpicc adds compiler specific flags and fails for older gcc versions

[Christian Engwer]

Package: libmpich-dev
Version: 3.1-5+b2
Severity: normal

Dear Maintainer,

the mpicc.mpich allows to exchange the underlying compiler via the "-cc="
parameter.

Calling
> mpicc.mpich -cc=gcc-4.8 test.c
fails, as gcc will complain about unknown compiler flags.
I'd expect that passing different compiler via -cc=... results working mpi
program.

%%%%%%%%%%

Let's look at this in a bit more details...

The problem underneath becomes obvious when asking for the compiler flags:

> mpicc.mpich -compile_info
gcc -D_FORTIFY_SOURCE=2 -g -O2 -fstack-protector-strong -Wformat -Werror
=format-security -Wl,-z,relro -I/usr/include/mpich -L/usr/lib/x86_64-linux-gnu
-lmpich -lopa -lmpl -lrt -lcr -lpthread

the output contains the "-fstack-protector-strong" parameter, which is not
available with gcc-4.8
alternatively you can ask via pkg-config

> pkg-config --cflags mpich
-D_FORTIFY_SOURCE=2 -g -O2 -fstack-protector-strong -Wformat -Werror=format-
security -I/usr/include/mpich

The problem is here that the actual compiler flags and the compiler are mixed.
When switching to use "-fstack-protector-strong" Debian basically decided to
use a different compiler, so in my opinion the right configuration is (in make-
style):
CC="gcc -fstack-protector-strong"
CFLAGS="-D_FORTIFY_SOURCE=2 -g -O2 -Wformat -Werror=format-security
-I/usr/include/mpich"

When the "-fstack-protector-strong" parameter is part of the compiler command,
the compiler can be exchanged without problems.



-- System Information:
Debian Release: stretch/sid
  APT prefers proposed-updates
  APT policy: (500, 'proposed-updates'), (500, 'oldoldstable'), (500, 'testing'), (400, 'stable'), (300, 'unstable'), (1, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 3.16.0-4-amd64 (SMP w/4 CPU cores)
Locale: LANG=de_DE.UTF-8, LC_CTYPE=de_DE.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages libmpich-dev depends on:
ii  g++         4:4.9.2-4
ii  gfortran    4:4.9.2-4
ii  libc6       2.19-18
ii  libcr-dev   0.8.5-2.2
ii  libcr0      0.8.5-2.2
ii  libmpich12  3.1-5+b2
ii  libmpl-dev  3.1-5+b2
ii  libopa-dev  3.1-5+b2

Versions of packages libmpich-dev recommends:
ii  mpich  3.1-5+b2

libmpich-dev suggests no packages.

-- no debconf information